All I know is what I read from people who are closer to the events than I am. I know it's gotta be frustrating for the troops on the ground who are bravely doing countless good things for the Iraqi people in trying to kill bad guys, get the lights and the water on, fix the smashed infrastructure and all the rest. I consider the troops on the ground heroic and always have. But I remain dubious that this Administration has a clue about what it is doing. That dichotomy is always present in my thoughts when I'm trying to evaluate what's happening in Iraq.
In other words, his fundamental position on the situation in Iraq is influenced more by his opinion of the administration (which, as we know from previous comments, is heavily influenced by the torture debate) than by the actual reports from the front. While this is somewhat defensible, I would hold that Mark clearly has a lot of emotional baggage (either "hate" or "righteous anger" depending on whether you're talking to me or him) when it comes to the Bush administration that makes him more or less irrational on the subject.
I also think, at the end of the day, Mark either does not follow or does not process much of the information he receives out of Iraq. For instance, he writes "We recently discovered that people we were training and equipping were part of the insurgency," as though he missed the entirety of the Fallujah Brigade story or the death squad activities that dominated the news through much of 2006. As long as he continues to exist within this willful ignorance, news stories can come and go but his emotional baggage towards the administration is likely to remain constant.